Summary

Recent archaeological excavations in Southwestern Spain have turned up a remarkable haul of weapons cut from rock crystal buried as grave goods in a series of stone-age1barrows. The majority of the pieces are arrowheads and microliths of the sort used for constructing a more complex edge2 but the dig also turned up a fairly impressive looking dagger blade.

Apparently creating these blades from rock crystal rather than more traditional flint or chert (or even, given the chalcolithic dating, the up and coming technology of copper) would have taken a significantly greater investment of time and effort. It's not clear if they were practical weapons, or ceremonial ones, deliberately selected to display wealth and prestige and buried as grave goods for the same reason.